std::unique
De cppreference.com
<metanoindex/>
<tbody> </tbody>| Definido no cabeçalho <algorithm>
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template< class ForwardIt > ForwardIt unique( ForwardIt first, ForwardIt last ); |
(1) | |
template< class ForwardIt, class BinaryPredicate > ForwardIt unique( ForwardIt first, ForwardIt last, BinaryPredicate p ); |
(2) | |
Remove todos os elementos consecutivos duplicados do
[first, last) alcance. A remoção é realizada por deslocamento do intervalo, quando necessário, de tal forma que os elementos a serem apagados são substituídos. Apenas o primeiro elemento de cada grupo de elementos iguais é deixado. Os elementos entre o velho eo novo fim ou o intervalo são deixados intactos. A primeira versão utiliza operator== para comparar os elementos, a segunda versão usa o predicado binário dado p.Original:
Removes all consecutive duplicate elements from the range
[first, last). Removing is done by shifting the range when needed in such a way that elements to be erased are overwritten. Only the first element in each group of equal elements is left. The elements between the old and the new end or the range are left intact. The first version uses operator== to compare the elements, the second version uses the given binary predicate p.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Parâmetros
| first, last | - | a gama de elementos ao processo
Original: the range of elements to process The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| p | - | binary predicate which returns true if the elements should be treated as equal. The signature of the predicate function should be equivalent to the following:
The signature does not need to have |
| Type requirements | ||
-ForwardIt must meet the requirements of ForwardIterator.
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-The type of dereferenced ForwardIt must meet the requirements of MoveAssignable.
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Valor de retorno
Transmitir iterador para o novo fim da amplitude
Original:
Forward iterator to the new end of the range
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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Possível implementação
| First version |
|---|
template<class ForwardIt>
ForwardIt unique(ForwardIt first, ForwardIt last)
{
if (first == last)
return last;
ForwardIt result = first;
while (++first != last) {
if (!(*result == *first)) {
*(++result) = *first;
}
}
return ++result;
}
|
| Second version |
template<class ForwardIt, class BinaryPredicate>
ForwardIt unique(ForwardIt first, ForwardIt last,
BinaryPredicate p)
{
if (first == last)
return last;
ForwardIt result = first;
while (++first != last) {
if (!p(*result, *first)) {
*(++result) = *first;
}
}
return ++result;
}
|
Exemplo
O código a seguir remove todos os elementos consecutivos equivalentes de um vetor de inteiros .
Original:
The following code removes all consecutive equivalent elements from a vector of integers.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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#include <iostream>
#include <algorithm>
#include <vector>
int main()
{
std::vector<int> v{1, 2, 2, 2, 3, 3, 2, 2, 1};
std::vector<int>::iterator last;
last = std::unique(v.begin(), v.end()); // 1 2 3 2 1 3 2 2 1
// ^
for (std::vector<int>::iterator it = v.begin(); it != last; ++it) {
std::cout << *it << " ";
}
std::cout << "\n";
}
Saída:
1 2 3 2 1
Complexidade
linear, em que a distância entre
first e lastOriginal:
linear in the distance between
first and lastThe text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.